一种新的基于先验数据表的JPEG-LS动态码率控制算法

摘要

JPEG-LS is suitable for the field of losslessear-lossless image compression because of its simple algorithm and high performance. However, it is difficult for JPEG-LS to control precisely the bit rate, which makes it hard to be applied to bandwidth-constrained occasions such as the satellite image coding. To solve this issue, the mathematic relation between bit rate and the quantization parameter is obtained by analyzing the coding characteristics of JPEG-LS, with which a novel dynamic bit-rate control algorithm is proposed based on the look-up table algorithm. Experimental results show that the proposed new bit-rate control algorithm is superior to the current JPEG-LS rate control scheme on the accuracy of bit-rate and the speed of bit-rate convergence.%JPEG-LS算法简单，压缩性能出众，特别适合应用在图像的无损/近无损压缩领域。但是，无法精确控制码率的缺点使得JPEG-LS难以应用在带宽受限的卫星图像编码领域。为了解决这个问题，该文基于对JPEG-LS编码特性的分析，通过理论推导得出输出码率与失真量化参数的数学关系，提出一种以查表算法为核心的新型JPEG-LS动态码率控制算法。相对于现有的动态码率控制算法，该算法具有码率精确度高，收敛速度快等优点。